In the field of diagnostic devices such as used in the medical device industry, especially those used for analysing blood or other bodily fluid samples, it is often required for users to monitor biometrics such as the levels of certain chemicals, substances, or analytes present for example in their bloodstream. For instance, diabetics in particular must regularly monitor the concentrations of glucose in their blood in order to determine if they are in need of insulin. In order to respond effectively to an individual's needs to monitor blood sugar levels, diagnostic devices and kits have been developed over the years to allow an individual to autonomously determine the concentration of glucose in their bloodstream, in order to better anticipate the onset of hyperglycaemia or hypoglycaemia and take preventative action as necessary. The existence of such diagnostic devices places less strain on the healthcare system at large, as patients are able to administer insulin in their own home and without having to do so in the presence of a medical professional.
Typically, the patient will perform a fingerstick to extract a small drop of blood from a finger or alternative site, using a lancing device. An electrochemical test strip is then inserted into a diagnostic meter, and the sample is applied to the test strip. Through capillary action, the sample flows across a measurement chamber of the strip and into contact with one or more electrodes or similar conductive elements coated in sensing chemistry for interacting with a particular analyte or other specific chemical (for example glucose) in the blood sample. The magnitude of the reaction is dependent on the concentration of the analyte in the blood sample. The diagnostic meter may detect the current generated by the reaction of the reagent with the analyte, and the result can be displayed to the user.
It is important that a correct test strip is used by a user. For example, a strip is generally designed to detect the presence of one or more analytes, and a user must ensure that, when requiring a measurement of a particular analyte, a strip capable of detecting such an analyte is used, as otherwise an incorrect reading will be given. In addition, proper identification of a test strip can avoid the accidental or purposeful use of a damaged/counterfeit strip, which could be of a relatively lower quality and potentially dangerous to the user.
US 2011/0139635 A1, US 2007/0068806 A1 and WO 2009/049015 A2 are examples of prior art strip identification methods wherein for example resistance measurements at a pair of electrodes are compared to the areas of the electrodes. Alternatively, electrodes may be formed of different materials, and the meter may be arranged to measure the impedance of the electrodes to identify a strip inserted in the meter.
There nonetheless remains a need in the art for new and improved methods of identifying electrochemical devices and electrochemical test strips in particular, to avoid the potential drawbacks identified above. The presently described embodiments seek to address this need.